Patents by Inventor Kuo-Chi Liu

Kuo-Chi Liu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 12362665
    Abstract: A power converter includes first to fourth switches, a flying capacitor, an inductor, an output capacitor and a control circuit. The first to fourth switches are sequentially coupled in cascode. The first switch receives an input voltage, and the fourth switch is further coupled to a ground terminal. The flying capacitor is coupled across the second switch and the third switch, the inductor is coupled to the second switch, the third switch and the output capacitor. The output capacitor is used to output an output voltage. In a non-regulated mode, the control circuit switches the first to fourth switches according to a resonant frequency. In a regulated mode, the control circuit switches the first to fourth switches according to a regulated frequency exceeding the resonant frequency. When the flying capacitor is coupled to the inductor, the flying capacitor and the inductor can form a resonant circuit having the resonant frequency.
    Type: Grant
    Filed: April 5, 2023
    Date of Patent: July 15, 2025
    Assignee: RICHTEK TECHNOLOGY CORP.
    Inventors: Kuo-Chi Liu, Ta-Yung Yang, Wei-Hsu Chang
  • Publication number: 20250202351
    Abstract: A resonant power converter includes a resonant capacitor, a transformer, a high-side transistor, a low-side transistor, a divider, a full-wave rectification device, a control circuit, and a rectifying circuit. The resonant capacitor is coupled between a resonant node and a ground. The transformer includes a primary coil coupled between a switch node and the resonant node and a secondary coil. The high-side transistor provides an input voltage to the switch node and the low-side transistor couples the switch node to the ground. The divider divides a voltage of the resonant node to generate a divided signal. The full-wave rectification device full-wave rectifies the divided signal to generate a full-wave rectified signal. The control circuit compares the full-wave rectified signal to a feedback voltage related to an output voltage to drive the high-side transistor and the low-side transistor. The rectifying circuit generates the output voltage.
    Type: Application
    Filed: July 24, 2024
    Publication date: June 19, 2025
    Inventors: Ta-Yung YANG, Yu-Chang CHEN, Kuo-Chi LIU, Tzu-Chen LIN
  • Publication number: 20250192672
    Abstract: A resonant power converter includes: a first and a second transistors, configured to form a half-bridge circuit; a resonant circuit including a resonant inductor, a primary winding of a transformer, and a resonant capacitor, which are serially coupled to each other, and wherein the first and the second transistors are configured to switch the resonant circuit to generate a resonant current for converting an input voltage into an output voltage; and a conversion control circuit configured to generate a ramp signal based on the resonant current, and to generate a first drive signal and a second drive signal based on the ramp signal and a compensation signal related to the output voltage. The first drive signal and the second drive signal are respectively used to control the first transistor and the second transistor. During a signal period of the ramp signal, the ramp signal monotonically increases or monotonically decreases.
    Type: Application
    Filed: July 31, 2024
    Publication date: June 12, 2025
    Inventors: Tzu-Chen Lin, Ta-Yung Yang, Kuo-Chi Liu
  • Publication number: 20250158513
    Abstract: A pre-bias voltage control circuit includes a flying capacitor, a voltage sensor, and a voltage controlled current source. The voltage sensor is used to generate a sensed capacitor voltage according to a capacitor voltage across the flying capacitor, and includes an inverting input terminal coupled to the flying capacitor, a non-inverting input terminal coupled to the flying capacitor, and an output terminal for outputting the sensed capacitor voltage. The voltage controlled current source is used to charge and discharge the flying capacitor, and includes a reference terminal for receiving a reference voltage, an input terminal coupled to the output terminal of the voltage sensor, a current output terminal coupled to the flying capacitor, and a current return terminal coupled to the flying capacitor. The voltage controlled current source generates a source current to charge the flying capacitor when the sensed capacitor voltage falls below the reference voltage.
    Type: Application
    Filed: April 22, 2024
    Publication date: May 15, 2025
    Inventors: Kuo-Chi Liu, Ta-Yung Yang, Chang-Yu Ho
  • Patent number: 12273035
    Abstract: A conversion control circuit controls plural stackable sub-converters which are coupled in parallel to generate an output power to a load, the conversion control circuit includes: a current sharing terminal, wherein a current sharing signal is configured to be connected to the current sharing terminals, in parallel, of the plurality of the conversion control circuits; and a current sharing circuit, configured to generate or receive the current sharing signal which is generated according to an output current of the output power; wherein the conversion control circuit adjusts the power stage circuit according to the current sharing signal for current sharing among the plural stackable sub-converters.
    Type: Grant
    Filed: March 21, 2023
    Date of Patent: April 8, 2025
    Assignee: Richtek Technology Corporation
    Inventors: Ta-Yung Yang, Wei-Hsu Chang, Kuo-Chi Liu, Chao-Chi Chen
  • Publication number: 20250112549
    Abstract: A switched capacitor converter for converting a first voltage into a second voltage and vice versa, includes: a plurality of switches which includes at least four switches, with a first switch included, which is coupled between the first voltage and an inductor switching node; an inductor coupled between the inductor switching node and the second voltage; a flying capacitor coupled to the plurality of switches and configured as a capacitive voltage divider; a current sense circuit for detecting an inductor current and sampling the inductor current during the first switch's turn-on state to generate a sensed current signal; an error amplifier for comparing the sensed current signal with a reference current signal to generate a first amplified signal; and a PWM generator for comparing the first amplified signal with a ramp signal for generating switching control signals to control a first switch current flowing to or from the first voltage.
    Type: Application
    Filed: May 13, 2024
    Publication date: April 3, 2025
    Inventors: Kuo-Chi Liu, Ta-Yung Yang
  • Patent number: 12199507
    Abstract: A multi-phase switching converter includes: first and second sub-switching converters; switching signals operating first and second capacitors of the first and second sub-switching converters to respectively perform a switched capacitor switching on a first voltage between plural electrical connection states, to respectively switch a first and second switching nodes between a first and second divided voltages of the first voltage obtained from the switched capacitor switching and a first and second reference voltage potentials thereby performing the power conversion between a first and second power nodes. Each of a first and second switch circuits of the first and second sub-switching converters has corresponding plural first and second switches and corresponding first and second subsidiary switch.
    Type: Grant
    Filed: December 1, 2023
    Date of Patent: January 14, 2025
    Assignee: Richtek Technology Corporation
    Inventors: Kuo-Chi Liu, Ta-Yung Yang
  • Patent number: 12199516
    Abstract: A multi-phase switching converter, includes: plural sub-switching converters; and a control circuit. Plural switching signals operate a capacitor of one of the plural sub-switching converters and a capacitor of another one of the plural sub-switching converters, to conduct a switched capacitor switching on a first voltage, thus switching an inductor switching node in each sub-switching converter between a divided voltage of the first voltage and a reference potential and to thereby execute a power conversion between the first voltage and a second voltage. When the inductors of each of the plural sub-switching converters are coupled with one another in a non-electromagnetic fashion, the multi-phase switching converters operate in a non-resonant mode. When the inductors of at least two of the plural sub-switching converters are electromagnetically coupled with one another, the multi-phase switching converters operate in a resonant mode or in the non-resonant mode.
    Type: Grant
    Filed: October 13, 2023
    Date of Patent: January 14, 2025
    Assignee: RICHTEK TECHNOLOGY CORPORATION
    Inventors: Kuo-Chi Liu, Ta-Yung Yang
  • Patent number: 12199506
    Abstract: A switched capacitor voltage converter circuit for converting a first voltage to a second voltage includes: an output capacitor; a switched capacitor converter; and a control circuit. The switched capacitor converter includes: a switch circuit including fourth switches; an inductor coupled between the switch circuit and the output capacitor; and a flying capacitor coupled to the switch circuit, wherein the flying capacitor and the output capacitor constitute a voltage divider. The control circuit generates a PWM signal according to the second voltage and generates switch signals according to the PWM signal to control the switch circuit, so as to convert the first voltage to the second voltage. The control circuit decides whether the switched capacitor converter operates in a boundary conduction mode, a discontinuous conduction mode or a continuous conduction mode according to an output current or an output current related signal.
    Type: Grant
    Filed: May 4, 2023
    Date of Patent: January 14, 2025
    Assignee: RICHTEK TECHNOLOGY CORPORATION
    Inventors: Kuo-Chi Liu, Ta-Yung Yang, Wei-Hsu Chang
  • Patent number: 12184168
    Abstract: A switched capacitor voltage converter circuit includes: a switched capacitor converter and a control circuit; wherein the control circuit adjusts operation frequencies and/or duty ratios of operation signals which control switches of the switched capacitor converter, so as to adjust a ratio of a first voltage to a second voltage to a predetermined ratio. When the control circuit decreases the duty ratios of the operation signals, if a part of the switches of the switched capacitor converter are turned ON, an inductor current flowing toward the second voltage is in a first state; if the inductor current continues to flow via a current freewheeling path, the inductor current flowing toward the second voltage becomes in a second state. A corresponding inductor is thereby switched between the first state and the second state to perform inductive power conversion.
    Type: Grant
    Filed: June 11, 2022
    Date of Patent: December 31, 2024
    Assignee: RICHTEK TECHNOLOGY CORPORATION
    Inventors: Kuo-Chi Liu, Ta-Yung Yang, Chung-Lung Pai
  • Patent number: 12176811
    Abstract: A switched capacitor voltage converter circuit includes: a switched capacitor converter and a control circuit. The switched capacitor converter includes at least one resonant capacitor, switches and at least one inductor. The control circuit generates a pulse width modulation (PWM) signal according to a first voltage or a second voltage and generates a control signal according to the PWM signal and a zero current detection signal. The control signal controls the switched capacitor converter by operating the corresponding switches to switch electrical connection of the inductor, so as to convert the first voltage to the second voltage or convert the second voltage to the first voltage.
    Type: Grant
    Filed: April 13, 2023
    Date of Patent: December 24, 2024
    Assignee: RICHTEK TECHNOLOGY CORPORATION
    Inventors: Kuo-Chi Liu, Ta-Yung Yang
  • Publication number: 20240413749
    Abstract: A multilevel buck converter includes a plurality of switches, an inductor, a flying capacitor, and a control circuit. The plurality of switches are coupled between an input terminal and a ground. The input terminal has an input voltage. The inductor is coupled between the plurality of switches and an output terminal for generating an inductor-current signal. The flying capacitor is coupled to the plurality of switches for generating a flying capacitor voltage. The control circuit is coupled to the output terminal and the plurality of switches for generating a plurality of switching signals according a feedback voltage and the inductor-current signal. The control circuit operates in a valley current mode with dual slope compensation.
    Type: Application
    Filed: August 31, 2023
    Publication date: December 12, 2024
    Inventors: Kuo-Chi Liu, Ta-Yung Yang, Yi-Min Shiu
  • Publication number: 20240405683
    Abstract: A multi-level switching converter circuit for converting a first voltage to a second voltage or convert the second voltage to the first voltage, includes: a power stage circuit and a control circuit. Through a valley current mode control, the conversion control circuit generates a first ramp signal to determine a first duty ratio of the first control signal, and generates a second ramp signal to determine a second duty ratio of the second control signal, thereby a switching node connected to one end of an inductor is switched between two of k levels of voltages, such that the first voltage or the second voltage is regulated to a predetermined target level, and a flying capacitor voltage across the flying capacitor is regulated and balanced at one (k-1)th of the first voltage.
    Type: Application
    Filed: March 5, 2024
    Publication date: December 5, 2024
    Inventors: Kuo-Chi Liu, Ta-Yung Yang
  • Publication number: 20240372467
    Abstract: A multi-phase conversion circuit includes: a first and a second sub-conversion circuits; multiple switching signals control the first front switch-mode capacitor conversion circuit's first front capacitor and the first rear switch-mode capacitor conversion circuit's first rear capacitor, and the second front switch-mode capacitor conversion circuit's second front capacitor and the second rear switch-mode capacitor conversion circuit's second rear capacitor to switch between plural electrical connection states. This setup performs switched capacitor voltage division on the first voltage, selectively switching the first or second switching node between the first or second divided voltage derived from the switched capacitor voltage division and a reference potential, whereby performing power conversion between the first power node and the second power node.
    Type: Application
    Filed: April 16, 2024
    Publication date: November 7, 2024
    Inventors: Kuo-Chi Liu, Ta-Yung Yang
  • Patent number: 12136877
    Abstract: A switched capacitor voltage converter circuit for converting a first voltage to a second voltage, includes: a switched capacitor converter and a control circuit. The switched capacitor converter includes at least two capacitors, plural switches and at least one inductor. In a mode switching period wherein the switched capacitor converter switches from a present conversion mode to a next conversion mode, at least two forward switches of the plural switches operate in a unidirectional conduction mode. Each of the forward switches provides a current channel that unidirectionally flows toward the second voltage in the unidirectional conduction mode. The switched capacitor voltage converter circuit is also operable to convert the second voltage to the first voltage.
    Type: Grant
    Filed: January 1, 2023
    Date of Patent: November 5, 2024
    Assignee: RICHTEK TECHNOLPGY CORPORATION
    Inventors: Kuo-Chi Liu, Ta-Yung Yang, Wei-Hsu Chang
  • Patent number: 12136875
    Abstract: A switched capacitor voltage converter circuit includes: a switched capacitor converter and a control circuit. In a charging process of a resonant operation mode, the switches in the switched capacitor converter operate to form a series connection of at least one capacitor and an inductor between a first voltage and a second voltage, as a charging path. In a discharging process of the resonant operation mode, the switches operate to form a series connection of each capacitor and the inductor between the second voltage and a ground level, thus forming plural discharging paths simultaneously or sequentially. In an inductor switching mode, the switches operate to couple one end of the inductor to the first voltage or the ground level alternatingly. The control circuit decides to operate in the resonant operation mode or the inductor switching mode according to the first voltage, thereby maintaining the second voltage within a predetermined range.
    Type: Grant
    Filed: October 25, 2022
    Date of Patent: November 5, 2024
    Assignee: RICHTEK TECHNOLOGY CORPORATION
    Inventors: Kuo-Chi Liu, Ta-Yung Yang
  • Patent number: 12136876
    Abstract: A switched capacitor voltage converter circuit includes: a switched capacitor converter, a control circuit and a zero current estimation circuit. The switched capacitor converter includes at least one resonant capacitor, switches and at least one inductor. The zero current estimation circuit is coupled to the at least one inductor and/or the at least one resonant capacitor, for estimating a time point at which a first resonant current is zero during a first process and/or a time point at which a second resonant current is zero during a second process according to a voltage difference between two ends of the inductor, and/or a voltage difference between two ends of the resonant capacitor, to a generate a zero current estimation signal accordingly for generating the operation signal.
    Type: Grant
    Filed: December 13, 2022
    Date of Patent: November 5, 2024
    Assignee: RICHTEK TECHNOLOGY CORPORATION
    Inventors: Kuo-Chi Liu, Ta-Yung Yang
  • Publication number: 20240297580
    Abstract: A multi-phase switching converter includes: first and second sub-switching converters; switching signals operating first and second capacitors of the first and second sub-switching converters to respectively perform a switched capacitor switching on a first voltage between plural electrical connection states, to respectively switch a first and second switching nodes between a first and second divided voltages of the first voltage obtained from the switched capacitor switching and a first and second reference voltage potentials thereby performing the power conversion between a first and second power nodes. Each of a first and second switch circuits of the first and second sub-switching converters has corresponding plural first and second switches and corresponding first and second subsidiary switch.
    Type: Application
    Filed: December 1, 2023
    Publication date: September 5, 2024
    Inventors: Kuo-Chi Liu, Ta-Yung Yang
  • Publication number: 20240235370
    Abstract: A multi-phase switching converter, includes: plural sub-switching converters; and a control circuit. Plural switching signals operate a capacitor of one of the plural sub-switching converters and a capacitor of another one of the plural sub-switching converters, to conduct a switched capacitor switching on a first voltage, thus switching an inductor switching node in each sub-switching converter between a divided voltage of the first voltage and a reference potential and to thereby execute a power conversion between the first voltage and a second voltage. When the inductors of each of the plural sub-switching converters are coupled with one another in a non-electromagnetic fashion, the multi-phase switching converters operate in a non-resonant mode. When the inductors of at least two of the plural sub-switching converters are electromagnetically coupled with one another, the multi-phase switching converters operate in a resonant mode or in the non-resonant mode.
    Type: Application
    Filed: October 13, 2023
    Publication date: July 11, 2024
    Inventors: Kuo-Chi Liu, Ta-Yung Yang
  • Publication number: 20240223086
    Abstract: A buck-boost switching converter for converting the power between a first and a second voltage, includes: a first sub-converter coupled between the first voltage and a first switching node, which includes a first plural switches and a capacitor; and a second sub-converter coupled between the second voltage and a second switching node, which includes a second plural switches. The first and second plural switches switch the capacitor and an inductor periodically, so as to divide the first voltage using the capacitor by a switched-capacitor (SC) voltage division method, and to switch the first switching node between a reference voltage and a voltage division of the first voltage, and to switch the second switching node between at least two voltages. The reference voltage is the first voltage, a ground or another voltage division of the first voltage. One of the at least two voltages is related to the second voltage.
    Type: Application
    Filed: September 20, 2023
    Publication date: July 4, 2024
    Inventors: Kuo-Chi Liu, Ta-Yung Yang